But what about UDP Port 113? On several security scans TCP Port 113 and UDP Port 113 were detected as OPEN. I am using a Linksys router and Kerio firewall with PPPoE DSL. In my router configuration, I managed to STEALTH TCP Port 113 by using UPnP and forwarding to a non existent IP address on my network. This technique does not work with the UDP Port 113, only the TCP Port. Can anybody advise me?